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Need engine logs opinion (injectors, map , maf)

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injectors logs map opinion
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Discussion starter · #21 · (Edited)
Happy new year!:xmas:

Just for discarding current and future possible problem sources, I fitted a new Bosch MAF, Pierburg boost control valve, and new boost sensor is on the way.
Just in case, I removed the battery for 1 hour, to reset the ecu. Although I didn't feel any noticeable difference.
The older maf measured 480mg/i at idle, while the new reads 500-510. Maybe caused just due the cold weather.
Also replaced the oil, oil filter, fuel filter, air filter and cabine air filter.

On full throttle, the boost gets around 1.3bar, and the maf reads ~1100mg/i.
EGR is still fully blanked, no boost leaks, neither vacuum leaks.
Swirl flaps still moving ok thanks to the repair kit.
But I think the air is a bit low? Without the maf I feel the car a bit better, but the maf is 100% genuine from bosch.
So...should I think on clogged intake manifold?



I made a (maybe useless) test. I took a small hose and placed it over each injector, then heard throught it.
Injector 1 and 5 made a lot more ticking noise than the rest. Does that mean anything?

Also, my car has lambda sensor, like the 159's. I have no idea how it works on a diesel, but since the car made smoke when it had the boost leak, I don't understand its function.
Shouldn't it measure the exhaust gasses, so the ecu checks if the mix is too lean or rich?
Cheers everyone.
 
Discussion starter · #26 ·
Yes, knocking usually means severe injector offset (bad connection, worn-out, dirty or carbon deposits...). Mine does it slightly from time to time, I believe that's directly related to the correction values.
I didn't had more starting problems since I fixed the swirl flaps control bar and blanked the EGR, so it can wait, I'm fixing the rear suspension first.
Regards
 
Discussion starter · #28 ·
I do have two injectors doing +-2, so probably they're almost KO.
Knocking canm be caused by a bad DMF flywheel too.. also a clogged intake, or damaged/loosen swirl flaps (nice work, EGR! )
Anyway it's much better to have a video to check the real sound.
 
Discussion starter · #29 · (Edited)
I did a log in 4th gear at full load.

Code: 
RPM		AIRE      	 presion	presion(deseada)	VNT  %
1304,0000	604,5000	1239,0000	1444,0000		73,3300	
1342,0000	669,5000	1375,0000	1541,0000		72,0610	
1400,0000	740,5000	1536,0000	1681,0000		71,1120	
1466,0000	843,5000	1752,0000	1884,0000		60,2780	
1544,0000	987,5000	2057,0000	2000,0000		51,0520	
1645,0000	1126,5000	2390,0000	2071,0000		34,8410	
1753,0000	1175,5000	2430,0000	2153,0000		50,5930	
1874,0000	951,5000	2019,0000	2242,0000		47,7550	
1988,0000	1126,0000	2270,0000	2287,0000		39,6780	
2112,0000	1206,0000	2435,0000	2301,0000		34,7710	
2235,0000	1196,5000	2381,0000	2316,0000		42,4370	
2354,0000	1131,5000	2271,0000	2327,0000		42,8060	
2482,0000	1139,0000	2306,0000	2337,0000		40,2180	
2599,0000	1162,5000	2336,0000	2350,0000		41,4070	
2714,0000	1108,5000	2249,0000	2361,0000		45,3250	
2829,0000	1099,5000	2242,0000	2380,0000		44,5260	
2939,0000	1119,0000	2287,0000	2399,0000		44,9060	
3048,0000	1134,0000	2338,0000	2395,0000		42,8560	
3159,0000	1153,5000	2386,0000	2391,0000		41,3280	
3264,0000	1142,0000	2393,0000	2374,0000		39,9280	
3370,0000	1116,5000	2354,0000	2354,0000		39,5090	
3471,0000	1096,0000	2328,0000	2334,0000		39,4980	
3573,0000	1081,5000	2315,0000	2314,0000		39,1590	
3671,0000	1071,5000	2304,0000	2296,0000		38,5380	
3763,0000	1058,0000	2294,0000	2277,0000		37,4400	
3847,0000	1039,0000	2271,0000	2261,0000		36,1500	
3931,0000	1016,0000	2255,0000	2243,0000		36,7700	
4009,0000	999,0000	2232,0000	2220,0000		35,8210	
4088,0000	982,5000	2206,0000	2195,0000		35,3900	
4158,0000	964,5000	2174,0000	2173,0000		35,3510	
4231,0000	945,0000	2155,0000	2154,0000		34,6720	
4294,0000	937,5000	2149,0000	2137,0000		34,3010	
4363,0000	915,5000	2125,0000	1648,0000		53,0010

Isn't it a bit weird? I'm waiting for the new MAP sensor to arrive, it could be bad.
I always noticed that the engine went flat over 3000, now I see why, the ECU is actually lowering the boost! Why?
This car always went to official Alfa service, so I'm proof that nobody else has touched it. However, MES shows that they've done one reprogramation at some moment.
Maybe they remapped the car to lower the high end power for some issue?

The vacuum pipes are ok, on idle the vnt moves when plugging/unplugging the pipe, althought the full displacement is a bit slow, around 2 seconds.
I see that it overboost a bit at 1600rpm and the ecu kicks in to lower the pressure.
I've read that on lower rpm the ecu controls the turbo with predefined values, while in the mid range it switches to closed-loop control, so any modifications to the intake/exhaust, like blanking EGR or removing DPF/cat causes overboost on lower revs, because doing so make the predefined values to go totally out of calibration. Am I right?
The vnt control valve and maf are new, swirl flaps moving, I didn't see the intake clogged, just had an oily soot layer but, nothing to worry about.

I just can't understand why the boost goes down over 3000rpm?

Cheers
 
#32 ·
In that graph it all looks very non-linear to me, as if airflow is being choked. Surely air quantity shouldn't diminish >3k rpm. Here it looks like the engine is getting less air than at lower revs, which can't be right. Hard to work out what is cause and what is effect, though.

Maybes:

A boost leak (split hose perhaps) that opens up as pressure increases

A new VNT actuator was fitted, but did you check VNT operation itself? Is it smooth and linear and not sticking? Easy to test with a vacuum gauge.

You will have the plastic swirl flaps. Despite the repair kit, which should have fixed air leaks at the manifold, I wonder if they aren't operating as they are supposed to due to accumulated oil+carbon gunge (from the EGR) obstructing the manifold.

Probably worth looking at the throttle body too.
 
Discussion starter · #33 ·
Throttle body is clean and shiny. I've rewed the engine to 3000 while checking the hoses. No leaks, also no smoke so I guess it's some airflow restriction somewhere.

So, I guess my only options now is to remove the manifold and turbo, and give then a clean and see the results
Thanks for the advices
 
#34 · (Edited)
cs155 stated reason above
the turbo boost map is shaped like this , to prevent it from damaging the turbo at higher revs and the efficiency also drops at the higher revs.
here is a std 20v jtdm boost map in 3d(probably the best turbo of the bunch)
say at 3000 revs it can supply a lot more boost as overall mass flow is lower at say x lbs/min
as the revs increase the airflow would be well off the turbo map if boost stayed at the same pressure , potentially over speeding the turbo.
try this open that last file in excel file and divide the actual boost pressure column by the actual maf airflow column and put the new value in an extra column , the result should be around 2.0 +/-0.2 for example.
like this of mine

View attachment boost divided by maf example.xls

by observing this figure it will give a good idea how boost and airflow act as revs increase , if as you suspect airflow is choked at higher revs this figure will vary more away from the mean figure as revs increase.
from your figs above
@2112revs 1206 2435 so 2435/1206=2.019
@3048revs 1134 2338 so 2338/1134=2.06
@3931revs 1016 2255 so 2255/1016=2.22

so rate of flow vs boost is slightly worse at high revs but I think this may be more the effect of maf saturation at high revs / high mass air flow rate. this is a common issue with higher tuned jtdm's and the reason some go to a larger maf sensor.

also think about boost temperature and its effect on mass air flow, as turbo efficiency goes down at the top end, boost temperature increases and therefore massirflow decreases for given boost, a reason most tuned turbo diesels look for more efficient intercoolers when increasing boost.

remind me what hp your car is as standard ? compared to the 210hp map I posted above your desired boost figures do look lower.(if you were guaranteed at full 100% pedal and max iq mm3. if you weren't may be reason peak figures are lower.
 
#36 · (Edited)
I cant see a matching file anywhere with 185hp but the 20v jtdm 200hp looks to match your boost figures desired pretty closely
so you can see here also how desired boost is reduced on std map.

to be sure you would need to log revs, total fuel mm3, desired boost and compare to this map .the least parameters you log the better the accuracy / speed of refresh rate etc.
then try revs , total fuel mm3 and actual boost pressure and actual airflow maf.
from this you could see what a/f ratio your running

other than the overboost underboost issue at lower revs boost control doesn't look too bad , have you done any exhaust mods , de cat de dpf etc.?
 
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